Go Back  Bike Forums > Bike Forums > Framebuilders
Reload this Page >

Different designs of seat stays, any differences?

Notices
Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

Different designs of seat stays, any differences?

Old 03-16-20, 05:49 AM
  #1  
Thomas1
Member
Thread Starter
 
Join Date: Oct 2016
Posts: 32
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked 0 Times in 0 Posts
Different designs of seat stays, any differences?

Hope this is the right forum to ask this question.
Browsing through bicycle adds Iíve noticed there are two different designs of seat stays: one where the seat stays are directly welded on to the seat tube and the other one where thereís an additional tube running down from the seat tube at the same angle as the seat stays do which is joined to the seat stays right over the wheel (please have a look at the pictures). The latter looks to me like some sort of rear version of the front fork. Is there any practical difference between them or advantage of one over the other? If that matters, Iím looking for a bicycle to be used as/converted to a commuter/touring bicycle.











Last edited by Thomas1; 03-16-20 at 02:42 PM. Reason: added another picture, title adjustment
Thomas1 is offline  
Old 03-16-20, 02:44 PM
  #2  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 19,562
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 294 Times in 231 Posts
top is called fastback and the one with the single tube is called a wishbone. The wishbone was invented to cut costs. There is no difference in the utility of the bikes.
unterhausen is offline  
Old 03-16-20, 06:35 PM
  #3  
Nessism
Senior Member
 
Nessism's Avatar
 
Join Date: Jun 2004
Location: Torrance, CA
Posts: 2,824

Bikes: Homebuilt steel

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Liked 30 Times in 26 Posts
Originally Posted by unterhausen View Post
top is called fastback and the one with the single tube is called a wishbone. The wishbone was invented to cut costs. There is no difference in the utility of the bikes.
How does wishbone cut costs?
Nessism is offline  
Old 03-16-20, 08:16 PM
  #4  
Doug Fattic 
framebuilder
 
Join Date: Dec 2009
Location: Niles, Michigan
Posts: 552
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 139 Post(s)
Likes: 0
Liked 137 Times in 73 Posts
I used to paint John Cherry frames. He liked to do a wishbone style. The lower part of the stays below the wishbone he made out of straight gauge !/2" tubing (obviously saving money over tapered tubing). He would make these in batches including the wishbone and single tube no matter what the size of the frame. The single tube above the wishbone could be mitered to length and angle after the rest of the frame was made to just fit that frame. Doing one miter and fillet brazing it to the back of the seat tube (with a necessary reinforcement) saved time over prepping and brazing two seat stay tops.
Doug Fattic is offline  
Old 03-16-20, 09:43 PM
  #5  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 13,283

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2321 Post(s)
Liked 400 Times in 318 Posts
There are far more important design aspects that will make or break a bike's intended use goal then whether the seat stays are full length of stop at the mono stay. Like fender clearance, rack mounts, cable routing paths.

I would also suggest that third and forth stay designs exist. The very common side of seat cluster attachment (as many millions of bikes have had for decades) and the Helenic (or as GT calls it, Triple Triangle). Still these don't really effect the bikes performance if all the more important details are done well.

I'm of the opinion that this stay stuff is far more about aesthetics and branding (see GT) then any structural aspect. The one possible exception might be aero drag reduction with a mono stay. Of course if the rider forgot to shave that day they just blew off any aero advantage Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 03-17-20, 08:24 PM
  #6  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 21,326

Bikes: Several, mostly not name brands.

Mentioned: 125 Post(s)
Tagged: 0 Thread(s)
Quoted: 2084 Post(s)
Liked 436 Times in 310 Posts
Originally Posted by Nessism View Post
How does wishbone cut costs?
It simplifies manufacturing. The seatstays can all be the same length, regardless of frame size, and straight-cut rather than mitered. The wishbone length varies with frame size, but only requires a single miter to join the seat tube.
JohnDThompson is offline  
Old 03-18-20, 06:36 AM
  #7  
Canaboo
Senior Member
 
Join Date: Dec 2009
Posts: 437
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Don't they still need mitered to join the larger tube?
Canaboo is offline  
Old 03-18-20, 07:54 AM
  #8  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 13,283

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2321 Post(s)
Liked 400 Times in 318 Posts
Originally Posted by Canaboo View Post
Don't they still need mitered to join the larger tube?
Yes the top of the SS will need joining to the mono stay tube somehow. Often with a rear version of a fork crown. But it's the ability to produce a single spec sub assembly ahead of need that helps make a mono stay slightly less costly for production bikes. (Instead of the 5 or 6 different sized SSs needed for the bike's available sizes). Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  
Old 03-18-20, 02:10 PM
  #9  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 19,562
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 294 Times in 231 Posts
You'll never see a bike with the wrong seat stays on it, like with some Treks.
unterhausen is offline  
Old 03-28-20, 10:18 AM
  #10  
repechage
Senior Member
 
Join Date: Jun 2006
Posts: 14,355
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 1326 Post(s)
Liked 287 Times in 232 Posts
I have a Grandis where the signature at the top is transposed left to right, it reads upside down.

There are plenty of "simplifications" seat stay top plugs were common but not commonly known in the 70's.
(think Colnago Super)
First wishbone seat stay example I saw was on a Freddy Parr built bike. Not that he was the first, just not common at all in the 70's.
Brian Baylis related that upon looking at Brian's Eisentraut A, Falerio dismissed it out of hand, as the seat stays were not brazed to the frame in the as he saw it, in the correct manner.
repechage is offline  
Old 03-28-20, 06:47 PM
  #11  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 19,562
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 294 Times in 231 Posts
That's pretty funny, Eisentraut made all the Europeans look like hacks.
unterhausen is offline  
Old 03-28-20, 08:16 PM
  #12  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 13,283

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2321 Post(s)
Liked 400 Times in 318 Posts
We had a bike in the boss's collection with a mono stay, employing a spring for a Moot's like suspension about 75 years before Moots was a brand. The bike was a shaft drive Columbia. So many bike ideas have been done so many times before. Andy
__________________
AndrewRStewart
Andrew R Stewart is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.